A UV/O3 cleaning method is widely used as a washing method in which ultraviolet rays and ozone (O3) which is an oxygen radical kind are used together. For example, molecular bonds of, for example, an organic compound adhering to a surface of a substrate for an LCD, or a semiconductor substrate are cut by emitting ultraviolet rays to the surface, so that impurities, such as an adhering organic compound can be removed.
In recent years, as a light source used for the UV/O3 cleaning method, instead of a conventional low-pressure mercury lamp which emits ultraviolet rays having wavelengths of 185 nm and 254 nm, an excimer lamp is used in which, for example, xenon gas is used as a light-emitting material so that a vacuum-ultraviolet light with a wavelength of 172 nm may be emitted, and the washing capacity thereof is superior to that of a low-pressure mercury lamp.
FIG. 7 is a cross-sectional view of a conventional ultraviolet-ray emitting apparatus in which an excimer lamp is installed, and FIG. 8 is a cross-sectional view of an ultraviolet-ray emitting apparatus taken along a line VIII-VIII of FIG. 7. Moreover, FIG. 9 is an enlarged cross-sectional view of the dotted line portion IX of FIG. 8. In addition, a connector shown in FIG. 8 is omitted in FIG. 7.
An ultraviolet-ray emitting apparatus has a metal case 10 in which inert gas is circulated through a gas introducing port 10b and a gas exhaust port 10c which are provided in side surfaces of the case. A plurality of excimer lamps 1 are disposed inside the case 10, in which tube axes are in parallel to each other. A gutter-like reflection mirror 2 which reflects ultraviolet rays emitted from the excimer lamp 1 toward a work piece is disposed corresponding to each excimer lamp 1. Each excimer lamp 1 for which the reflection mirror 2 is fixed to a cooling block 3 made of aluminum, in which a water-cooled pipe is piped throughout the interior.
Such an excimer lamp 1 is shown in Japanese Laid Open Patent No. 2005-100934. As shown in FIG. 8, sealing portions 1f are formed at both ends of an arc tube 1a made from dielectric material which transmits vacuum-ultraviolet light, by pinch-sealing the both ends, in each of which a metallic foil 1e is buried. Inside the arc tube 1a, while a coil-like internal electrode 1b, both ends of which are connected to the respective metallic foils 1e, is arranged on the tube axis of the arc tube 1a, the circumference of the internal electrode 1b is covered with an insulator 1d. Moreover, on an outer surface of the arc tube 1a, a mesh-like external electrode 1c is arranged. An external lead 1g which projects toward the outside of the arc tube 1a is connected to each metallic foil 1e. A high voltage power supply cable 12c is connected to one of the external leads 1g, in which a high voltage power supply terminal 12 is provided at an end portion thereof (Refer to FIG. 9).
As shown in FIG. 9, a high voltage power supply terminal 12 comprises a plug 12a to which the electric supply cable 12c is connected, and an insulated holder 12b, in which the electric supply cable 12c is inserted. The tip of the plug 12a connected to the electric supply cable 12c projects toward the outside from the insulated holder 12b, and the electric supply cable 12c, the insulated holder 12b, and plug 12a are integrally formed. The internal electrode 1b and a high-frequency lighting power supply (not shown) are electrically conducted (connected) by inserting the plug 12a in the connector 11 whose casing is made of resin, which is attached to the outer wall of the case 10. Although the external electrode 1c is not illustrated, the electrode 1c is electrically conducted (connected) with the high frequency lighting power supply similarly the internal electrode.
If the above excimer lamp reaches the end of life span thereof, the intensity of radiation of vacuum ultraviolet radiation decrease as the quartz glass etc. forming the arc tube is deteriorated. Therefore, although it is necessary to replace it with a new one, it is in general difficult to determine whether it reached the end of the life span from the appearance of the excimer lamp. Thus, there is a demand that integral lighting time information be added to each excimer lamp. Moreover, if the physical-property information of each excimer lamp etc. is given in addition to the integral lighting time information, it is advantageous when lighting of a lamp is controlled.
Here, the lamp physical-property information includes but is not limited to information of the light intensity property, that is, information that the luminance is 1 lm (lumen) per 100 W of input power at a portion downwardly apart by 10 mm from the arc tube, or load property information, that is, information that unusual electric discharge does not take place when the input power is less than 100 W.
Here, Japanese Laid Open Patent No. 2003-68478 discloses the technology of making each lamp have integral lighting time information in the light source apparatus used for an endoscope etc. in order to know the end of the life span of the lamp.
According to this light source apparatus, since the integral lighting time information which is updated up to the last usage is stored in an IC tag (comprising such as a chip or an integrated circuit) attached to the lamp unit, when the light is turned on, the integral lighting time information can be updated to the latest information as needed by updating and storing the integral lighting time information in the IC tag. Therefore, if the IC tag is attached to each excimer lamp shown in FIG. 7, it is possible to give integral lighting time information to each excimer lamp, and to predict certainly the end of life span of each excimer lamp.